Philly RiverCast

RiverCast considers the historic relationships between rainfall, river flow, and water clarity (or turbidity) to river bacteria levels to produce a recreational water quality rating that aligns with USEPA recommendations.

The time required to analyze a water quality sample for bacteria is greater than one day and would not allow for hourly water quality ratings. Instead, Philly RiverCast produces an hourly forecast of probable bacteria ranges using an algorithm that considers real-time turbidity, flow, and precipitation data. This algorithm is periodically compared to results from bacteria sampling in the same stretch of the Schuylkill to ensure accuracy.

A “red” rating may be produced by heavy rainfall, upstream rain events that impact downstream conditions, turbid (cloudy) water, and/or high stream flows.

RiverCast Water Quality Designations are based on historical relationships between water quality, streamflow, and rainfall data, and on the United States Environmental Protection Agency’s “Implementation Guidance for Ambient Water Quality Criteria for Bacteria” (USEPA, 2002). This document identifies the maximum acceptable bacteria levels measured in a single sample for waters where recreational activities involving complete immersion in water may occur.
The historical data analysis compiled bacteria and turbidity (water clarity) data collected by the Philadelphia Water Department in the vicinity of the Fairmount Pool (Manayunk to Boathouse Row) from 1998 to 2000, along with rainfall and streamflow data from the US Geological Survey for the same location and time period. This data was analyzed to identify flow, rainfall and turbidity conditions that correspond to bacteria levels defined by the federal regulations for recreational waters. This guidance defines when it is or is not safe to have direct or indirect contact with the water.

Water quality in a river is affected by many factors, including weather, climate, rainfall, upstream wastewater discharges, and accidental spills. It is strongly impacted by runoff from rain events. This is easily observed during and after storms when streams and rivers are very cloudy and appear brown. When it rains, the dirt, animal waste, and other contaminants that build up on the surface of the ground or pavement are washed into streams and rivers. Though there is more water in the streams and rivers during storms, there are more contaminants as well.

Swimming and bathing in Philadelphia’s rivers and streams are only permitted during organized events (e.g., races, triathlons, etc.) due to risks of drowning, injury from submerged objects, strong currents, and other hazards.

No, RiverCast was developed by examining the relationships between precipitation, flow, turbidity (water clarity), and bacteria concentrations in the stretch of the Schuylkill River from Boathouse Row to Manayunk, and it should only be used as guidance for recreational activity in that stretch of the river.

Generally, the Philadelphia Water Department does not sponsor or host any of these events. Accordingly, the decision to postpone or cancel an event due to water quality conditions is ultimately left up to the event host. We strongly encourage potential participants and event hosts to consider the Philly RiverCast rating and the rating’s limitations in combination with other information sources (e.g. policies, regulations, public health statements, empirical data, observations, water exposure type and duration, and other potential health or environmental risks) prior to deciding whether or not to participate in or host such events.

Many of the risks of recreating in the river are the same for pets as for their owners. Strong currents, drowning, and unseen objects such as fishhooks or glass fragments are a threat to even the best of swimmers. Pets should never be left unattended at the river. If a pet does become immersed in the river, it should be thoroughly bathed afterwards.

Seek medical attention for any injury that occurs while recreating on the river. Wounds should be managed through careful cleaning, control of bleeding, and examination for the possible presence of unexpected foreign material. It is also important to ensure that your tetanus immunization status is up to date.